The present invention relates to an improved technique for coking mixtures of petroleum residua and shale oil residua and in particular to an improvement over commonly assigned application Ser. No. 080,830, filed Oct. 1, 1979.
In prior application Ser. No. 080,830, the disclosure of which is incorporated herein by reference, it was disclosed that liquid product yields produced by coking can be unexpectedly increased by the expedient of using as the coking feed a mixture of a shale oil residuum and a petroleum residuum. Since liquid products produced by coking are generally more valuable than the solid coke product, this invention has significant commercial advantage.
However, it would be even more valuable if the liquid product yields could be increased over and above the amounts realized when a mixture of shale oil residuum and petroleum residuum is coked in accordance with that invention, and accordingly it is an object of the present invention to provide a process for coking a mixture of shale oil residuum and petroleum residuum which is capable of producing even greater liquid yields.